Rotationally static light emitting material with rotating optics

ABSTRACT

A system including a rotationally static light emitting material with rotating optics is provided. The system comprises: the material on a heatsink being circularly symmetrical around an axis, and rotationally fixed; a stationary light source configured to generate excitation light, the excitation light configured to excite the material producing emitted light, an incoming path of the excitation light forming a first angle, with the axis greater than 0° and less than 90°; and, optics, configured to rotate relative to the material around the axis, comprising: a first mirror on the axis and forming a second angle with the axis greater than 0° and less than 90°, the first mirror located on the incoming path; and a second mirror parallel to the first mirror, the first mirror configured to reflect the excitation light towards the second mirror, and the second mirror configured to reflect the excitation light towards the material.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation-in-part application of U.S. patentapplication Ser. No. 14/444,283, filed Jul. 28, 2014, which isincorporated herein by reference.

FIELD

The specification relates generally to light generation systems, andspecifically to a rotationally static light emitting material withrotating optics.

BACKGROUND

In laser-light emitting materials illumination systems, a limitingfactor to the product performance is the cooling of the light emittingmaterial, for example a phosphor. One of the benefits of putting thephosphor on a rotating wheel is that it distributes the incident energyover a larger area, effectively decreasing the heat density. When arotating liquid-cooled phosphor wheel is used in high powerapplications, however, it is necessary to contain a cooling liquid usinga rotating seal. Rotating seals have a finite lifespan, which may beless than what is desired for the illumination source or for theprojector application. Furthermore, high energy density in a spot of alight emitting material can result in degradation in performance of thematerial.

SUMMARY

In general, this disclosure is directed to a rotationally static lightemitting material with rotating optics. An input path (and alternativelyan output path) of excitation light(including, but not limited to laserlight) and an output path of light are fixed along a rotational axis ofoptics that rotate about a rotationally fixed light emitting materialand heatsink, to distribute light production at the light emittingmaterial over the surface of the heatsink, so that a static heat sinkcan be used to cool the light emitting material, for example a waterblock, heat pipes, vapour chambers, heat spreaders and the like. Atleast a portion of the rotationally static light emitting material hascircular symmetry, and the rotating optics are coaxial with therotationally static light emitting material; the rotating optics arerotated using a motor, and the like about the light emitting material.Excitation light is received at the optics along the rotational axis,and the optics convey the excitation light to the rotationally staticlight emitting material as the optics are rotating, sweeping out acircle of the excitation light on the rotationally static light emittingmaterial. The excitation light excites the light emitting material,which in turn emits light; the light is collected by the rotating opticswhich conveys the light produced by the light emitting material back tothe rotational axis, where the light exits the optics, for exampletowards collection optics and/or projector optics so that images can beproduced from the emitted light, e.g. in a projector system. As theexcitation light is collected along the rotational axis, and the emittedlight exits the optics along the rotational axis, the positions of thelaser and the collector optics are fixed. Further, as the light emittingmaterial is rotationally static, the light emitting material is locatedon a rotationally static heatsink; hence the heatsink can be cooledusing a rotationally static heatsink, including waterblocks, obviatingthe use of a rotating seal. As the optics cause the excitation light toilluminate the light emitting material by sweeping out a circle, and thelike, heat generation at the light emitting material is also spread outover the circle, preventing heat build up at one spot on the lightemitting material without rotation of the light emitting material. Theheatsink/light emitting material can be linearly translated paralleland/or perpendicularly to the optics so that the excitation light sweepsout a spiral type shape on the light emitting material in order tofurther spread out heat generation on the light emitting material. Insome implementations, the stationary light source can be off-axis andthe rotating optics comprise two parallel mirrors. In otherimplementations, the light emitting material can comprise a gainmaterial of a thin disc laser; in some of these implementations, systemsdescribed herein can include one or more retroreflectors configured torecycle light reflected from a mirror of the thin disc laser back to thegain material for further light production.

In this specification, elements may be described as “configured to”perform one or more functions or “configured for” such functions. Ingeneral, an element that is configured to perform or configured forperforming a function is configured to perform the function, or issuitable for performing the function, or is adapted to perform thefunction, or is operable to perform the function, or is otherwisecapable of performing the function.

It is understood that for the purpose of this specification, language of“at least one of X, Y, and Z” and “one or more of X, Y and Z” can beconstrued as X only, Y only, Z only, or any combination of two or moreitems X, Y, and Z (e.g., XYZ, XYY, YZ, ZZ, and the like). Similar logiccan be applied for two or more items in any occurrence of “at least one. . . ” and “one or more . . . ” language.

An aspect of the specification provides a system comprising: a heatsink;at least one light emitting material located on the heatsink, at least aportion of the at least one light emitting material being circularlysymmetrical around an axis, the heatsink and the at least one lightemitting material being rotationally fixed; optics configured to rotaterelative to the at least one light emitting material around a rotationalaxis that is coaxial with the axis of the at least one light emittingmaterial, the optics configured to: receive excitation light along therotational axis; convey the excitation light to one or more locations onthe light emitting material as the optics are rotating; collect lightemitted from the one or more locations on the light emitting materialexcited by the excitation light; and, convey the light collected fromthe at least one light emitting material to the rotational axis foremission there along.

The system can further comprise a motor configured to rotate the opticsrelative to the at least one light emitting material.

The system can further comprise at least one stationary light sourceconfigured to generate the excitation light.

The system can further comprise: at least one stationary light sourceconfigured to generate the excitation light; and stationary optics forconveying the excitation light to the optics along the rotational axis.

The system can further comprise one or more of a body and a frame, oneor more of the body and the frame comprising the optics.

The system can further comprise one or more of a body and a frame, oneor more of the body and the frame comprising the optics and a counterbalance so that a center of mass of one or more of the body and theframe is located along the rotational axis.

The optics can comprise one or more of: at least one dichroic mirror; atleast one lens; and at least one prism.

A surface of the heatsink and the at least one light emitting materialcan comprise an annulus symmetrical about the axis, and the optics arefurther configured to rotate along the surface.

The heatsink can comprise a cylinder, and the at least one lightemitting material can be located on an interior surface of the cylinder,the optics configured to rotate within the cylinder.

The heatsink can comprise a cylinder, and the at least one lightemitting material can be located on an exterior surface of the cylinder,the optics further configured to rotate around the exterior surface ofthe cylinder.

The at least one light emitting material can comprise at least two lightemitting materials located at different portions of the heatsink, eachof the at least two light emitting materials being circularly symmetricabout the axis, the optics further configured to convey the excitationlight to each of the at least two light emitting materials as the opticsare rotating.

The optics can be further configured to: convey the excitation light toat least two different portions of the at least one light emittingmaterial; collect the light emitted from the at least two differentportions excited by the excitation light; and convey the light collectedfrom the at least two different portions to the rotational axis foremission there along.

The system can further comprise apparatus for displacing the heatsinkrelative to the optics.

The heatsink can further comprise a static waterblock.

The heatsink can comprise a toroid symmetrical about the axis.

The heatsink can comprise a toroid symmetrical about the axis and theoptics are configured to one or more of: receive the excitation lightthrough the toroid; and convey the light collected from the at least onelight emitting material through the toroid.

The optics can be further configured to receive the excitation lightfrom a first side of the optics and convey the light collected from theat least one light emitting material back through the first side.

The optics can be further configured to receive the excitation lightfrom a first side of the optics and convey the light collected from theat least one light emitting material through a second side opposite thefirst side.

The light emitting material can be located on opposing sides of theheatsink and the optics can be further configured to receive theexcitation light from both of the opposing sides of the heatsink.

A further aspect of the specification provides a system comprising: aheatsink; a light emitting material located on the heatsink, at least aportion of the light emitting material being circularly symmetricalaround an axis, the heatsink and the light emitting material beingrotationally fixed; a stationary light source configured to generateexcitation light, the excitation light configured to excite the lightemitting material to produce emitted light, an incoming path of theexcitation light forming a first angle with the axis of the lightemitting material, the first angle being greater than 0° and less than90°; and, optics configured to rotate relative to the light emittingmaterial around the axis of the light emitting material, the opticscomprising: a first mirror located on the axis and forming a secondangle with the axis, the first mirror further located on the incomingpath of the excitation light, the second angle being greater than 0° andless than 90°; and a second mirror parallel to the first mirror, thefirst mirror configured to reflect the excitation light towards thesecond mirror, and the second mirror configured to reflect theexcitation light towards the light emitting material.

A reflected path of the excitation light from the first mirror to thesecond mirror to the light emitting material can be about equal to alength of a line extending along the incoming path of the excitationlight from a first intersection point between the first mirror and theincoming path and a second intersection point between the axis and theline.

The first mirror and the second mirror can be further configured toreflect the emitted light from the light emitting material away from thelight emitting material.

The first mirror and the second mirror can be further configured toreflect the emitted light from the light emitting material away from thelight emitting material along the axis.

The first angle can be greater than about 20° and less than about 75°.

The second angle can be greater than about 20° and less than about 75°.

The system can further comprise: at least a second stationary lightsource configured to generate the excitation light, a respectivegeometry of a respective incoming path of the excitation light from theat least a second stationary light source similar to a geometry of theincoming path of the excitation light from the stationary light source.

A portion of the second mirror can be located on the path of theexcitation light between the stationary light source and the firstmirror, the portion of the second mirror configured to: transmit theexcitation light towards the first mirror; and reflect the excitedlight.

The portion of the second mirror located on the path of the excitationlight between the stationary light source and the first mirror cancomprise one or more of: a dichroic mirror; and, when the excitationlight and the emitted light have different polarization states, apolarizing beamsplitter.

A centre of the first mirror can be located on the axis.

The system can further comprise one or more of a body and a frame, oneor more of the body and the frame comprising the optics.

The system can further comprise a motor configured to rotate the opticsrelative to the light emitting material.

The system can further comprise one or more of a body and a frame, oneor more of the body and the frame comprising the optics and a counterbalance so that a center of mass of one or more of the body and theframe can be located along the rotational axis.

A surface of the heatsink and the light emitting material can comprisean annulus symmetrical about the axis, and the optics can be furtherconfigured to rotate along the surface.

The heatsink further can comprise a static waterblock.

A further aspect of the specification provides a system comprisingsystem comprising: a heatsink; a gain medium of a thin disc laserlocated on the heatsink, at least a portion of the gain medium beingcircularly symmetrical around an axis, the heatsink and the gain mediumbeing rotationally fixed; optics configured to rotate relative to thegain medium around a rotational axis that is coaxial with the axis ofthe at least one light emitting material, the optics configured to:receive excitation light; convey the excitation light to the gain mediumat an off-normal angle as the optics are rotating; collect light emittedfrom the gain medium excited by the excitation light; and, conveyemitted light away from the gain medium; and, at least oneretroreflector configured to reflect the excitation light reflected froma mirror of the thin disc laser back towards the gain medium.

The optics can comprise the at least one retroreflector such that the atleast one retroreflector rotates.

The at least one retroreflector can be static.

The at least one retroreflector can comprise at least one flat mirror.

The at least one retroreflector can comprise a combination of at leastone parabolic mirror and at least one prism retroflector.

The at least one retroreflector can comprise at least one prismretroreflector.

The at least one retroreflector can comprise a combination of one ormore of at least one flat mirror, at least one parabolic mirror, and atleast one prism retroreflector arranged to reflect the excitation lightreflected from the mirror of the thin disc laser back towards the thindisc laser.

The excitation light can be coincident with the axis of rotation and theoptics can be further configured to receive the excitation light alongthe axis of rotation.

The excitation light can be not coincident with the axis of rotation andthe optics can be further configured to receive the excitation light offof the axis of rotation.

The system can further comprise one or more of a body and a frame, oneor more of the body and the frame comprising the optics.

The system can further comprise a motor configured to rotate the opticsrelative to the gain medium.

The system can further comprise one or more of a body and a frame, oneor more of the body and the frame comprising the optics and a counterbalance so that a center of mass of one or more of the body and theframe can be located along the rotational axis.

A surface of the heatsink and the gain medium can comprise an annulussymmetrical about the axis, and the optics can be further configured torotate along the surface.

The heatsink further can comprise a static waterblock.

BRIEF DESCRIPTIONS OF THE DRAWINGS

For a better understanding of the various implementations describedherein and to show more clearly how they may be carried into effect,reference will now be made, by way of example only, to the accompanyingdrawings in which:

FIG. 1 depicts a side view, and a partial cross-sectional view, of asystem that includes a rotationally static light emitting material withrotating optics, according to non-limiting implementations.

FIG. 2 depicts a path of excitation light through the system of FIG. 1,according to non-limiting implementations.

FIG. 3 depicts a path of light emitted from a light emitting materialthrough the system of FIG. 1, according to non-limiting implementations.

FIG. 4 depicts the system of FIG. 1 with rotating optics moved to adifferent position as compare to FIG. 1, according to non-limitingimplementations.

FIG. 5 depicts a front perspective view of the heatsink and lightemitting materials of FIG. 1, as well as a path of excitation lightimpinging on the light emitting material, according to non-limitingimplementations.

FIG. 6 depicts a front perspective view of an alternative heatsink andlight emitting materials, according to non-limiting implementations.

FIG. 7 depicts a side view, and a partial cross-sectional view, of analternative system that includes a rotationally static light emittingmaterial with rotating optics, according to non-limitingimplementations.

FIG. 8 depicts a side view, and a partial cross-sectional view, of analternative system that includes a rotationally static light emittingmaterial with rotating optics, according to non-limitingimplementations.

FIG. 9 depicts a side view, and a partial cross-sectional view, of analternative system that includes a rotationally static light emittingmaterial with rotating optics, according to non-limitingimplementations.

FIG. 10 depicts a side view, and a partial cross-sectional view, of analternative system that includes a rotationally static light emittingmaterial with rotating optics, according to non-limitingimplementations.

FIG. 11 depicts a side view, and a partial cross-sectional view, of analternative system that includes a rotationally static light emittingmaterial with rotating optics, according to non-limitingimplementations.

FIG. 12 depicts a front perspective view of an alternative heatsink andlight emitting materials, according to non-limiting implementations.

FIG. 13 depicts a side view, and a partial cross-sectional view, of analternative system that includes a rotationally static light emittingmaterial with rotating optics, according to non-limitingimplementations.

FIG. 14 depicts a side view, and a partial cross-sectional view, of analternative system that includes a rotationally static light emittingmaterial with rotating optics, according to non-limitingimplementations.

FIG. 15 depicts a side view, and a partial cross-sectional view, of analternative system that includes a rotationally static light emittingmaterial with rotating optics, according to non-limitingimplementations.

FIG. 16 depicts a side view, and a partial cross-sectional view, of analternative system that includes a rotationally static light emittingmaterial with rotating optics, according to non-limitingimplementations.

FIG. 17 depicts a side view, and a partial cross-sectional view, of analternative system that includes a rotationally static light emittingmaterial with rotating optics for collecting light emitted on oppositesides of a heatsink, according to non-limiting implementations.

FIG. 18 depicts a side view, and a partial cross-sectional view, of asystem that includes a rotationally static light emitting material withrotating optics, with a path of incoming excitation light being off arotational and/or circular axis of the rotating optics and/or the lightemitting material, according to non-limiting implementations.

FIG. 19 depicts a path of emitted light through the system of FIG. 18,according to non-limiting implementations.

FIG. 20 depicts the system of FIG. 18 with the rotating optics rotatedabout 180° relative a position of the rotating optics in FIG. 18,according to non-limiting implementations.

FIG. 21 depicts geometrical relationships in the system of FIG. 18,according to non-limiting implementations.

FIG. 22 depicts a side view, and a partial cross-sectional view, of asystem that includes a rotationally static light emitting material withrotating optics, with a path of incoming excitation light being off arotational and/or circular axis of the rotating optics and/or the lightemitting material, and with at least a portion of the rotating opticsbeing at least partially transparent to the excitation light, accordingto non-limiting implementations.

FIG. 23 depicts a side view, and a partial cross-sectional view, of asystem that includes a plurality of stationary light sources and arotationally static light emitting material with rotating optics, with apath of incoming excitation light being off a rotational and/or circularaxis of the rotating optics and/or the light emitting material,according to non-limiting implementations.

FIG. 24 depicts a thin disc laser structure, according to non-limitingimplementations.

FIG. 25 depicts a side view, and a partial cross-sectional view, of asystem that includes a rotationally static thin disc laser with rotatingoptics, and a retroreflector, according to non-limiting implementations.

FIG. 26 depicts a side view, and a partial cross-sectional view, of asystem that includes a rotationally static thin disc laser with rotatingoptics, and a retroreflector, according to alternative non-limitingimplementations.

FIG. 27 depicts a side view, and a partial cross-sectional view, of asystem that includes a rotationally static thin disc laser with rotatingoptics, and two retroreflectors, according to alternative non-limitingimplementations.

FIG. 28 depicts a retroreflected path of the excitation light throughthe system of FIG. 27, according to alternative non-limitingimplementations.

DETAILED DESCRIPTION

FIG. 1 depicts a side view, and partial cross-sectional view, of asystem 100 comprising a heatsink 101; at least one light emittingmaterial 103 located on heatsink 101, at least a portion of at least onelight emitting material 103 being circularly symmetrical around an axis105, heatsink 101 and at least one light emitting material 103 beingrotationally fixed; and, optics 107 configured to rotate relative to atleast one light emitting material 103 around a rotational axis 109 thatis coaxial with axis 105 of at least one light emitting material 103. Asdescribed below, optics 107 are configured to: receive excitation lightalong rotational axis 109; convey the excitation light to one or morelocations on at least one light emitting material 103 as optics 107 arerotating; collect light emitted from the at one or more locations on theat least one light emitting material 103 excited by the excitationlight; and, convey the light collected from at least one light emittingmaterial 103 to rotational axis 109 for emission there along. It isappreciated that, in FIG. 1, heatsink 101 and light emitting material103 are depicted in cross-section, and comprise a toroid and/or annulus,the cross-section being along a diameter of the toroid and/or annulus;furthermore, optics 107 are depicted schematically. At least one lightemitting material 103 will be interchangeably referred to hereafter aslight emitting material 103.

Indeed, as depicted system 100 further comprises one or more of a bodyand a frame (the body and/or frame hereinafter referred to as frame 111)that comprises optics 107. Frame 111 rotates on one or more bearings 113located along an outer edge of frame 111; alternatively, bearings 113can be located at a hub (not depicted) of frame 111. System 100 furthercomprises a motor 115 configured to rotate frame 111, and hence optics107, relative to light emitting material 103. For example, motor 115 caninteract with frame 111 to rotate frame 111, on bearings 113, aboutrotational axis 109. Motor 115 can rotate frame 111 using a belt (notdepicted) and/or other device for translating rotational motion to frame111. Alternatively motor 115 can comprise a ring motor and/or any othertype of motor configured to rotate frame 111. Indeed, any device forrotating frame 111 around rotational axis 109 is within the scope ofpresent implementations.

In some implementations, system 100 and/or frame 111 is rotationallysymmetric such that a center-of-mass of frame 111 is located alongrotational axis 109. In other implementations, as depicted, frame 111further comprises an optional counter-balance 116 located so that acentre-of-mass of frame 111 is located along rotational axis 109. Forexample, as optics 107 are generally asymmetric with respect to frame111 (i.e. optics 107 are located off-centre from rotational axis 109),when frame 111 and optics 107 are rotated, vibration can occur due tothe centre-of-mass of optics 107 being off of rotational axis 109;counter-balance 116 can hence be located on an opposite side of frame111 to optics 107 to counter-balance optics 107 during rotation andreduce the possibility of vibration of frame 111 and optics 107.

As depicted system 100 further comprises at least one stationary lasersource 117 configured to generate the excitation light, interchangeablyreferred to hereafter as laser 117. However, laser 117 can alternativelybe replaced with any light source that will generate excitation light,and the light source need not be a laser. Hence, while excitation lightin system 100 can comprise laser light, any excitation light that willexcite light emitting material 103 to emit light is within the scope ofpresent implementations. For example, excitation light is generallylight that is of a shorter wavelength than light emitted by lightemitting material 103. Indeed, light emitting material 103 caninterchangeably be referred to as a light conversion material as lightemitting material 103 converts excitation light having a firstwavelength into emitted light having a second wavelength longer than thefirst wavelength.

As depicted, laser 117 (and/or an excitation light source) is locatedalong rotational axis 109, however in other implementations laser 117can be located off rotational axis 109. For example, as depicted, system100 further comprises an optional second laser 127 (and/or secondexcitation light source) and optional stationary optics 130 forconveying excitation light from laser 127 to optics 107 along rotationalaxis 109. As depicted stationary optics 130 comprises a dichroic mirrorlocated along a rotational axis 109, and along a path of excitationlight emitted from laser 117, and along a path of excitation lightemitted from laser 127; the dichroic mirror is configured to combineexcitation light from lasers 117, 127 so that the excitation light isconveyed to optics 107 along rotational axis 109. For example,excitation light from laser 117 passes through dichroic mirror to optics107, while excitation light from laser 117 is reflected along rotationalaxis 109 into optics 107. Hence, whether a laser is on or off rotationalaxis 109, excitation light from a laser in system 100 is received atoptics 107 along rotational axis 109.

Each of laser 117 and optional laser 127 can comprise a blue lasersource of similar or different wavelengths. For example, in someimplementations, laser 117 can comprise a laser source of about 448 nmand laser source 127 can comprise a laser source of about 465 nm.Furthermore, while light sources described herein are described withreference to lasers, in other implementations, system 100 can compriselight sources different from lasers.

In yet further implementations, system 100 can comprise one or moreintegrating rods (not depicted) located along an excitation light pathof each of lasers 117, 127 for integrating excitation light there from.

Optics 107 comprises one or more of at least one dichroic mirror; atleast one mirror; at least one lens; and at least one prism. As depictedoptics 107 comprise a first prism 140, a second prism 141, and lenses143. Each of prisms 140, 141 can comprise reflection surfaces, includingbut not limited to total internal reflection surfaces, at opposite endsfor reflecting light and/or excitation light either through eachrespective prism 140, 141 and/or out of each prism. In someimplementations, each of the reflection surfaces can include with amirror and/or a dichroic mirror. Alternatively each reflection surfaceof each prism 140, 141 can include and/or be replaced by a mirror and/ora dichroic mirror so that angles of the surfaces to the body do not haveto be controlled to be total internal reflection angles.

Lenses 143 comprise one or more lenses configured to focus excitationlight on light emitting material 103, and collect light emitted by lightemitting material 103, and convey the light emitted by phosphor backthrough prism 141, as described in more detail below. While three lenses143 are depicted, lenses 143 can comprise fewer than three lenses ormore than three lenses.

As depicted, system 100 further comprises collection optics, locatedalong rotational axis 109 (and/or axis 105), which can include, but isnot limited to one or more lenses 150 and an integrator 151. Thecollection optics can be rotational and/or stationary; for example lens150 can rotate with optics 107, and integrator 151 can be stationary oralso rotate with optics 107. Collection optics can convey light emittedfrom optics 107 along rotational axis 109 and/or axis 105 to, forexample, a light modulator (not depicted) and the like. Indeed, one ormore of collection optics can be elements of projection optics for aprojector. Collection optics can comprise one or more lenses, one ormore integrating rods, optical fibers, and/or any other optical elementsfor collecting light emitted from optics 107 along rotational axis 109and/or conveying light emitted from optics 107 along rotational axis 109to a projector and the like. As depicted, lens 150 collects lightemitted from optics 107 (i.e. light emitted by light emitting material103 which has been collected by lenses 143 and conveyed to rotationalaxis 109 by prism 141), and conveys the light to an input of integrator151, which in turn conveys the light to a light modulator, and the like.As depicted, the light is conveyed through an aperture of toroidalheatsink 101, located at a geometric centre of heatsink 101; however, inother implementations, the light can be conveyed along a same path asexcitation light input to optics 107 and reflected towards collectionoptics using a dichroic mirror and the like.

It is further appreciated that relative sizes and thicknesses ofelements in FIG. 1 are not to scale. For example, a thickness of lightemitting material 103 relative to dimensions of heatsink 101 is notdepicted to scale; further, a gap between lenses 143 and light emittingmaterial 103 is not depicted to scale.

Light emitting material 103 can include, but is not limited to, one ormore of a phosphor, a ceramic phosphor, quantum dots, a luminescentmaterial, a fluorescent material, and the like; indeed, while presentimplementations will be described with regard to ceramic phosphors,other light emitting materials are within the scope of presentimplementations. Specifically, light emitting material 103 comprises anymaterial that emits light when excited by excitation light, and thelike.

For example, in some implementations, light emitting material 103 can beconfigured for excitation by blue excitation light (e.g. from laser 117and/or laser 127), and emit light of a wavelength longer than the blueexcitation light, including, but not limited to, red light and greenlight. Further, in some implementations, light emitting material 103comprises more than one light emitting material located, for example, insegments on heatsink 101, as described below with respect to FIG. 6. Forexample, one or more segments of light emitting material 103 can emitred light, while one or more other segments of light emitting material103 can emit green light; hence, when heatsink 101 and light emittingmaterial 103 comprises a light emitting wheel, as depicted, as optics107 rotate, the blue excitation light, and the like interacts with thedifferent segments of light emitting material 103.

Furthermore, in some implementations, light emitting material 103 can belocated on a reflective surface of heatsink 101 so that light emittedfrom light emitting material 103 towards heatsink 101 is reflected awayfrom heatsink 101 towards optics 107, as described below.

System 100 can generally be used in a projection system (not depicted),in which, for example, blue excitation light excites light emittingmaterial 103, which emits red light and/or green light and/or yellowlight, the blue excitation light, the emitted light providing RGB(red-green-blue) light and/or white light to the projection system.Alternatively, light emitting material 103 can emit blue light in theRGB/white system.

In general, the process of exciting light emitting material 103 to emitlight results in the production of heat which is to be dissipated toprevent light emitting material 103 and heatsink 101 from heating upand/or to control a temperature of light emitting material 103. As lightemitting material 103 emits light, heat flows into heatsink 101 from theinterface between light emitting material 103 and heatsink 101, the heatbeing dissipated at heatsink 101. Hence, heatsink 101 comprises one ormore of a heatsink, a block, a wheel, a ring, one or more extrusions orother heat sink design (e.g. for air cooling), a water-block, a vapourchamber, a heat spreader, and the like, configured to cool lightemitting material 103. Heatsink 101 can comprise any material configuredto cool light emitting material 103 including, but not limited to,metal, aluminum, steel and the like. Further, as depicted, heatsink 101comprises a plate of material with nominally circular symmetry, thoughother shapes are within the scope of present implementations, including,but not limited to, a square, a rectangle and the like. Indeed shapesthat do not have circular symmetry are within the scope of presentimplementations: for example, heatsink 101 can be rectangular, withadjacent segments of different light emitting material; however, atleast of portion of light emitting material 103 has circular symmetryaround axis 105.

Attention is next directed to FIGS. 2 and 3 which depict system 100 inoperation; FIGS. 2 and 3 are substantially similar to FIG. 1 with likeelements having like numbers. In FIG. 2 motor 115 interacts with frame111 to rotate optics 107 about rotational axis 109, as indicated byarrow 201. For example, with respect to FIG. 2, optics 107 are rotatedout of the page above rotational axis 109 and into the page belowrotational axis 109, though the terms “out”, “into”, “above” and “below”are used for descriptive purposes only and system 100 can have anysuitable orientation, for example within a projection system. Further,lasers 117, 127 are operated to emit excitation light 203: excitationlight 203 from laser 117 passes through the dichroic mirror ofstationary optics 130 along rotational axis 109 towards an entrance faceof prism 140, and excitation light 203 from laser 127 is reflected bythe dichroic mirror along rotational axis 109 towards the entrance faceof prism 140. Frame 111 hence comprises an aperture and the like so thatexcitation light 203 enters prism 140.

An input and/or an entrance face and a first reflection surface 205 ofprism 140 is located along rotational axis 109; first reflection surface205 can comprise one or more of a total internal reflection surface, amirror, a dichroic mirror and the like, and is configured to reflectexcitation light 203 about perpendicular to rotational axis 109 along abody of prism 140, the body of prism 140 also being about perpendicularto rotational axis 109 (i.e. along a rotational radius of a path ofoptics 107). Surface 205 can hence be at about 45° to rotational axis109. Excitation light 203 enters prism 140 along rotational axis 109 andis reflected through the body of prism 140 towards a second reflectionsurface 207, which is configured to reflect excitation light 203 towardslight emitting material 103, for example through an end of prism 141 andthrough lenses 143. Surface 207 can hence also be at about 45° torotational axis 109.

Excitation light 203 then impinges on light emitting material 103, asdescribed below with respect to FIG. 3. As also depicted in FIG. 2,prism 141 comprises a first reflection surface 209 and a secondreflection surface 211 separated by a body; first reflection surface 209is located on a path of excitation light 203 as excitation light 203 isreflected from surface 207 towards light emitting material 103; hencesurface 209 is configured to transmit excitation light 203 there throughand comprise one or more of: a total internal reflection surface forlight impinging on surface 209 in a direction opposite a path ofexcitation light 203; and a dichroic mirror.

Attention is next directed to FIG. 3 where light 303 emitted from lightemitting material 103 upon excitation by excitation light 203 iscollected by lenses 143. Though excitation light 203 is not depicted inFIG. 3 for clarity, excitation light 203 is nonetheless present (forexample, see FIG. 4); indeed, excitation light 203 can excite lightemitting material 103 in a generally constant manner, such that light303 is also emitted constantly. In any event, lenses 143 collect light303, which can be emitted as a cone, and the like (e.g. light 303 has anetendue), and lenses 143 direct light 303 towards reflection surface209. Surface 209 reflects light 303 towards reflection surface 211,about perpendicular to rotational axis, through a body of prism 141.Surface 209 can hence be at about 45° to rotational axis 109. Prism 141is hence also about perpendicular to rotational axis 109 (i.e. along arotational radius of a path of optics 107).

Reflection surface 211 is located along rotational axis 109, and isconfigured to reflect light 303 out of prism 141, for example through anexit face (and/or an output of optics 107), along rotational axis 109and towards lens 150, which in turn focuses light 303 onto an input ofintegrator 151 through an aperture of heatsink 101. Surface 211 canhence be at about 45° to rotational axis 109. As well, frame 111 isappreciated to comprise an aperture and the like between prism 141 andlens 150 so that light 303 can exit frame 111.

In some implementations, light 303 can be emitted over a plurality ofangles, including, but not limited to a cone, or other shape, and thelike, each of lenses 143, 150 and surfaces 209, 211 can be of a sizeand/or geometry and/or location to collect a substantial portion and/orall of light 303. For example, as depicted, edges of light 303 passthrough lenses 143 which in turn convey light 303 towards surface 209;surface 209 is of a size and location to contain the edges of light 303,as is the body of prism 141; surface 211 is similarly of a size andlocation to contain edges of light 303, which can be collimated withinthe body of prism 141. Alternatively total internal reflection withinthe body of prism 141 can contain light 303 therein. Light 303 can begenerally collimated when exiting prism 141, and an entrance surface oflens 150 can be larger than edges of light 303 as light 303 impinges onlens 150. Lens 150 generally focuses light 303 onto integrator 151,which integrates light 303 and conveys light 303 towards projectionoptics, and the like.

As excitation light 203 is being conveyed to light emitting material 103through optics 107, and as optics 107 are collecting and conveying light303 to collection optics, optics 107 are rotating relative to lightemitting material 103. As an input (e.g. one or more of an entrance faceof prism 140 and reflection surface 205) and an output (e.g. one or moreof an exit face of prism 141 and reflection surface 211) of optics 107are located on rotational axis 109, optics 107 conveys excitation light203 to light emitting material 103, and conveys light 303 to collectionoptics, regardless of where optics 107 are located on a rotation path.In other words, each reflection surface 205, 211 are located on rotationaxis 109 and rotate about rotation axis 109. Further, the input and anoutput of optics 107 can be about centred on rotational axis 109. Hence,regardless of where optics 107 are located on a rotation path, surface205 collects excitation light 203 into optics 107 and surface 211conveys light 303 out of optics 107.

For example, attention is next directed to FIG. 4 which depicts system100 after optics 107 have been rotated through 180° relative to FIGS. 2and 3; indeed, FIG. 4 is substantially similar to FIGS. 2 and 3 withlike elements having like numbers. However, in FIG. 4, optics 107 havebeen rotated to a location on a rotation path, opposite and/or 180° froma location in FIGS. 2 and 3. Again, as an input (e.g. one or more of anentrance face of prism 140 and reflection surface 205) and an output(e.g. one or more of an exit face of prism 141 and reflection surface211) of optics 107 are located on rotational axis 109, optics 107conveys excitation light 203 to light emitting material 103, and conveyslight 303 to collection optics, regardless of where optics 107 arelocated on a rotation path.

Hence, optics 107 are generally configured to: receive excitation light203 along rotational axis 109, as in FIGS. 2 and 4, for example bylocating surface 205 along rotational axis 109; convey excitation light203 to at least one light emitting material 103 as the optics arerotating, for example via surfaces 205, 207; collect light 303 emittedfrom at least one light emitting material 103 excited by excitationlight 203, as in FIGS. 3 and 4, for example using lenses 143; and,convey light 303 collected from at least one light emitting material 13to rotational axis 109 for emission there along, as in FIGS. 3 and 3,for example using lenses 143, and surfaces 209, 211.

Furthermore, as depicted in FIGS. 2-4, as optics 107 rotate with respectto light emitting material 103, hence excitation light 203 inscribes acircular path on light emitting material 103, as depicted in FIG. 5.Indeed, FIG. 5 depicts a front perspective view of heatsink 101 andlight emitting material 103, as well as a circular path 501 thatexcitation light 203 impinges on light emitting material 103. Hence,production of light 303 also occurs on path 501, as well as heatproduction and dissipation into heatsink 101; as heatsink 101 does notrotate, heatsink 101 can comprise a static waterblock with a staticseal, which can comprise a coolant inlet 503 and a coolant outlet 505.

Furthermore, while light emitting material 103 is depicted in FIGS. 1-5as covering a substantial area of a surface of heatsink 101, lightemitting material 103 can be located in a band, for example a circularband, around path 501. Indeed, light emitting material 103 can have anygeometry on heatsink 101, though a portion of light emitting material103 generally has circular symmetry in the area of path 501.

Persons skilled in the art will appreciate that there are yet morealternative implementations and modifications possible. For example,system 100 can further comprise apparatus for linearly displacingheatsink 101 relative to optics 107; such apparatus (not depicted) caninclude a linear motor and the like which can be configured to linearlymove one or more of frame 111 and heatsink 101 in one or more directionsparallel to each other so that path 501 becomes a spiral, and the like,to dissipate heat over a larger area of heatsink 101. As heatsink 101does not rotate, even when linearly translated, a static water seal canbe used to with a waterblock of heatsink 101, as in FIG. 5.

In yet further implementations, the light emitting material can comprisered light emitting segments and green light emitting segments of lightemitting material. For example, attention is next directed to FIG. 6which depicts a heatsink 601, similar to heatsink 101, and lightemitting materials 603R, 603G, arranged in circularly consecutivesegments on heatsink 601. Light emitting material 603R is configured toemit red light while light emitting material 603G is configured to emitgreen light. Light emitting materials 603R, 603G will be interchangeablyreferred to hereafter as light emitting materials 603. Heatsink 601 andlight emitting materials 603 can be used in system 100 in place ofheatsink 101 and light emitting materials 103 to produce a mixture ofred and green light. While light emitting materials 603 are depicted inwedges, light emitting materials 603 can alternatively be portions of aband of light emitting materials. Further, while red and green lightemitting materials are depicted, in other implementations, lightemitting materials 603 can include red, green and blue light emittingmaterials so that when light from all three light emitting materials arecombined, white light is produced.

Alternatively, heatsink 601 and light emitting materials 603R, 603G canbe used in a system similar to system 100 to produce white light. Forexample, attention is next directed to attention is next directed toFIG. 7, which depicts a system 600 that is substantially similar tosystem 100, with like elements having like numbers, but starting with a“6” rather than a “1”. Hence, system 600 comprises: heatsink 601; leastone light emitting material 603 (i.e. light emitting materials 603R,603G) located on heatsink 601; and, optics 607 configured to rotaterelative to at least one light emitting material 603 around a rotationalaxis 609 that is coaxial with axis 605 of at least one light emittingmaterial 603. System 600 further comprises a frame 611, bearings 613, amotor 615, a counter-balance 616, a laser 617 (only once laser isdepicted for simplicity, however in other implementations, system 600can comprise two or more lasers), one or more lenses 650 and anintegrator 651. Laser 617 can comprise a blue laser emitting blueexcitation light 673.

Optics 607 comprises prisms 640, 641, having reflection surfaces 665,667, 669, 671, and lenses 643, similar to lenses 143. Reflectionsurfaces 667, 669 are respectively similar to reflection surfaces 207,209. However, reflection surface 665 is configured to reflect a portion674 of excitation light 673 emitted from laser 617, and transmit aportion 675 there through towards surface 671; and surface 671 isaligned with surface 665 along rotational axis 609, and surface 671 isconfigured to reflect light 683 emitted from light emitting material 603(i.e. red light and green light) and transmit portion 675 (i.e. bluelight) there through, to combine with light 683, at least at integrator651, to produce white light for use, by example, in a projection system.Reflection surfaces 665, 671 are otherwise respectively similar toreflection surfaces 205, 211.

In yet further implementations, prisms 140, 141 can be replaced with oneor more mirrors and one or more dichroic mirrors. For example, attentionis next directed to FIG. 8, which depicts a system 800 that issubstantially similar to system 100, with like elements having likenumbers, but starting with an “8” rather than a “1”. Hence, system 800comprises: a heatsink 801; at least one light emitting material 803located on heatsink 801; and, optics 807 configured to rotate relativeto at least one light emitting material 803 around a rotational axis 809that is coaxial with axis 805 of at least one light emitting material803. System 800 further comprises a frame 811, bearings 813, a motor815, a counter-balance 816, lasers 817, 827, stationary optics 830, oneor more lenses 850 and an integrator 851.

In contrast to system 100, however, optics 807 comprises lenses 843,similar to lenses 143, and mirrors 865, 867, 869, 871, rather thanprisms 140, 141. Mirrors 865, 867, 869, 871 are located at positionsrespectively similar to surfaces 205, 207, 209, 211; mirrors 865, 867are displaced by a distance similar to length of prism 140, and mirrors869, 871 are displaced by a distance similar to a length of prism 141.Further, while each of mirrors 865, 867, 871 can comprise a reflectivemirror and/or a dichroic mirror, mirror 869 comprises a dichroic mirrorwhich transmits excitation light as it reflects from mirror 867 tolenses 843, and reflects light received from light emitting material 803through lenses 843 towards mirror 871. Hence, mirrors 865, 867, 869, 871have similar functionality as prisms 140, 141, and can be more efficientthan prisms 140, 141 as excitation light from lasers 117, 127 travelthrough air there between rather than a solid optical material such asglass and/or plastic and/or the like.

Heretofore, implementations have been described where rotating opticscomprise two prisms and/or four mirrors, however other optics are withinthe scope of the present specification.

For example, attention is next directed to FIG. 9, which depicts asystem 900 that is substantially similar to system 100, with likeelements having like numbers, but starting with a “9” rather than a “1”.Hence, system 900 comprises: a heatsink 901; at least one light emittingmaterial 903 located on heatsink 901; and, optics 907 configured torotate relative to at least one light emitting material 903 around arotational axis 909 that is coaxial with axis 905 of at least one lightemitting material 903. System 900 further comprises a frame 911,bearings 913, a motor 915, a counter-balance 916, one or more lasers917, one or more lenses 950 and an integrator 951. In contrast to system100, however, laser 917 is located on a side of heatsink 901 oppositeoptics 907, and lens 950 and integrator 951 are located on same side ofheatsink 901 as optics 901; in other words, as compared to laser 117 andintegrator 151 of system 100, in system 900, locations of optics 907 andintegrator 951 have been exchanged. Hence, a path of excitation light983 (solid line in FIG. 9) from laser 917 is through an aperture ofheatsink 601.

Furthermore, optics 907 comprise: lenses 943, similar to lenses 143,dichroic mirrors 965, 971 and mirror 967 rather than prisms 140, 141.Dichroic mirrors 965, 971 can also be referred as a dichroic structure.Dichroic mirror 965 is located on rotational axis 905, and is alignedwith laser 917 so that dichroic mirror 965 reflects light 983 from laser917 away from rotational axis 905 towards mirror 967, which in turnreflects excitation light 983 through lenses 943 to light emittingmaterial 903. Light emitting material 903 is then excited and emitslight 993, similar to light 303, which collected by lenses 943, andconveyed to mirror 967, which reflects light 983 towards dichroic mirror971, which reflects light 983 along rotational axis 909 and out of frame911 towards lens 950, which convey and/or focus light 993 onto an inputof integrator 951.

Hence, each of dichroic mirrors 965, 971 are located on rotational axis909, about centred on rotational axis 909, and are each at about 45° torotational axis 909. Further, dichroic mirror 965 is reflective ofexcitation light 983, and transparent to light 983 so that light 983 isnot transmitted back towards laser 917. In some implementations,dichroic mirror 965 is partially transmissive to excitation light 983 sothat a portion of excitation light 983 is mixed with light 993 at leastat integrator 951, as in system 600. Dichroic mirror 971 is reflectiveof light 993 and transmissive to excitation light 983.

In some implementations, a lens and the like can be located on a path ofexcitation light 983 between laser 917 and dichroic mirror 965 to betterfocus excitation light 983 onto dichroic mirror 965. In yet furtherimplementations system 900 can include (in addition to lens 950) amirror, and the like for reflecting light 993 (and alternatively aportion of excitation light 983) towards collection optics, and thelike.

Heretofore, implementations have been discussed in which at least onelaser and collection optics are on opposite sides of a heatsink androtating optics; however, the present specification includesimplementations where at least one laser and collection optics can be ona same side of a heatsink and rotating optics.

For example, attention is next directed to FIG. 10, which depicts asystem 1000 that is substantially similar to system 100, with likeelements having like numbers, but starting with a “10” rather than a“1”. Hence, system 1000 comprises: a heatsink 1001; at least one lightemitting material 1003 located on heatsink 1001; and, optics 1007configured to rotate relative to at least one light emitting material1003 around a rotational axis 1009 that is coaxial with axis 1005 of atleast one light emitting material 1003. System 1000 further comprises aframe 1011, bearings 1013, a motor 1015, a counter-balance 1016, one ormore lasers 1017, one or more lenses 1050 and an integrator 1051. Incontrast to system 100, however, laser 1017, one or more lenses 1050 andan integrator 1051 are located on a same side of heatsink 1001.

System further comprises a stationary dichroic mirror 1070 located on anintersection of a path of excitation light 1083 emitted from laser 1017,and a path of light 1093 emitted from light emitting material 1003 andconveyed to integrator 1051 by optics 1007, as described hereafter, androtational axis 1009. In some implementations, system 1000 can includeat least dichroic structure configured to reflect a portion ofexcitation light 1083 towards integrator 1051 to combine with light1093, and transmit a remaining portion of excitation light 1083 towardsoptics 1007, as in system 600.

Optics 1007 comprise a mirror 1065 located on rotational axis 1009 (andcentred on rotational axis 1009) and a mirror 1067 locatedperpendicularly from rotational axis 1009, mirror 1065 configured toreflect excitation light 1083 towards mirror 1067, and reflect light1093 received from mirror 1067 towards integrator 1051 and/or collectionoptics, and the like. Mirror 1067 is configured to reflect excitationlight 1083 reflected from mirror 1065 towards light emitting material1003, and reflect light 1093 received from light emitting material 1003(as collected by lenses 1043), towards mirror 1065. Each of mirrors1065, 1067 is at about 45° to rotational axis 1009. In someimplementations, mirrors 1065, 1067 can be replaced by a prism, as insystem 100.

In other words, a wide variety of rotating optics are within the scopeof present implementations, as long as excitation light is receivedalong a rotational axis thereof, and light collected from a lightemitting material is conveyed back to the rotational axis for emissionthere along.

The present specification can further include at least two lightemitting materials located at different portions of a heatsink, each ofthe at least two light emitting materials being circularly symmetricabout an axis, and rotating optics can be further configured to conveyexcitation light to each of the at least two light emitting materials asthe rotating optics are rotating. Furthermore, the rotating optics canbe further configured to: convey the excitation light to at least twodifferent portions (e.g. one or more locations) of the at least onelight emitting material; collect the light emitted from the at least twodifferent portions excited by the excitation light; and convey the lightcollected from the at least two different portions to a rotational axisfor emission there along.

For example, attention is next directed to FIG. 11, which depicts asystem 1100 that is substantially similar to system 900, with likeelements having like numbers, but starting with an “11” rather than a“9”. Hence, system 1100 comprises: a heatsink 1101; at least one lightemitting material 1103-1, 1103-2 located on heatsink 1101; and, optics1107 configured to rotate relative to at least one light emittingmaterial 1103-1, 1103-2 around a rotational axis 1109 that is coaxialwith axis 1105 of at least one light emitting material 1103-1, 1103-2.System 1100 further comprises a frame 1111, bearings 1113, a motor 1115,a counter-balance 1116, one or more lasers 1117, one or more lenses 1150and an integrator 1151. In contrast to system 900, however, system 1100comprises two light emitting materials 1103-1, 1103-2, each circularlysymmetric about axis 1105. For example, attention is directed to FIG.12, which depicts a front perspective view of heatsink 1101, which issimilar to heatsink 901 and/or heatsink 101, and light emittingmaterials 1103-1, 1103-2, each located at different radii around axis1105, with light emitting material 1103-1 having larger radii than lightemitting material 1103-2. In yet further implementations, system 1100can include more than two light emitting materials with circularsymmetry on heatsink 1101, each at different radii.

With further reference to FIG. 11, optics 1107 is generally configuredto: convey excitation light 1183 from laser 1117 to at least two lightemitting materials 1103-1, 1103-2 at different radii from rotationalaxis 1109; collect light 1193-1, 1193-2 emitted from the at least twolight emitting materials 1103-1, 1103-2 excited by excitation light1183; and convey light 1193-1, 1193-2 collected from at least two lightemitting materials 1103-1, 1103-2 to rotational axis 1109 for emissionthere along.

For example, optics 1107 comprise a dichroic structure 1165 which issimilar to the combination of dichroic mirrors 965, 971, a mirror 1167,similar to mirror 967, and lenses 1143-1, similar to lenses 943; furthermirror 1167 and lenses 1143-1 are configured to receive excitation light1183 from dichroic structure 1165, convey excitation light 1183 to lightemitting material 1103-1, collect light 1193-1 from light emittingmaterial 1103-1 emitted when excited by excitation light 1183, andconvey light 1193-1 to dichroic structure 1165, which conveys light1193-1 to integrator 1151.

However, in contrast to optics 907, optics 1107 further comprise asecond dichroic structure 1168 located between dichroic structure 1165and mirror 1167, on a path of excitation light 1183 there between, andsecond lenses 1143-2. Second dichroic structure 1168 is configured toconvey a portion of excitation light 1183 towards light emittingmaterial 1103-2 (and lenses 1143-2), and convey a remaining portion ofexcitation light 1183 to mirror 1167. Hence, dichroic structure 1168 islocated between dichroic structure 1165 and mirror 1167 at a radius thatis similar to a radius of light emitting material 1103-2. Further,lenses 1143-2 are configured to collect light 1193-2 emitted from lightemitting material 1103-2, and convey light 1193-2 to dichroic structure1168. Dichroic structure 1168 is hence further configured to reflectlight 1193-2 to dichroic structure 1165 and/or combine light 1193-1received from mirror 1167 and convey combined light 1193 (comprisinglight 1193-1, 1193-2) to integrator 1151.

Indeed, in yet further implementations, system 1100 can comprise morethan two light emitting materials located on heatsink 1101 at differentradii, and optics 1107 can include corresponding lenses and a dichroicand/or reflective structure for each located between mirror 1167 anddichroic structure 1165.

In yet further implementations, rotating optics can be configured toconvey excitation light to at least two different portions of lightemitting material, for example, in different directions from arotational axis of the rotating optics at a same or different radius.

For example, attention is next directed to FIG. 13, which depicts asystem 1300 that is substantially similar to system 900, with likeelements having like numbers, but starting with a “13” rather than a“9”. Hence, system 1300 comprises: a heatsink 1301; at least one lightemitting material 1303 located on heatsink 1301; and, optics 1307configured to rotate relative to at least one light emitting material1303 around a rotational axis 1309 that is coaxial with axis 1305 of atleast one light emitting material 1303. System 1300 further comprises aframe 1311, bearings 1313, a motor 1315, one or more lasers 1317, one ormore lenses 1350 and an integrator 1351. In contrast to system 900,however, system 1300 comprises one or more light emitting materials 1303circularly symmetric about axis 1305.

Further, in contrast to optics 907, optics 1307 is generally configuredto: convey excitation light 1383 from laser 1317 to at least twodifferent portions of light emitting material 1303; collect light1393-1, 1393-2 emitted from the at least two different portions of lightemitting material 1303 excited by excitation light 1383; and conveylight 1393-1, 1393-2 collected from the at least two different portionsof light emitting material 1303 to rotational axis 1309 for emissionthere along.

For example, optics 1307 comprise a dichroic structure 1365 which issimilar to the combination of dichroic mirrors 965, 971, however,dichroic structure 1365 is configured to convey excitation light 1383 intwo different directions: as depicted, dichroic structure 1365 isconfigured to convey excitation light 1383 in two different directionsabout 180° from each other, however in other implementations, dichroicstructure 1365 can be configured to convey excitation light 1383 indirections different from at about 180° to each other.

Optics 1307 further comprises a mirror 1367-1, similar to mirror 967,and lenses 1343-1, similar to lenses 943. However, optics 1307 furthercomprises a mirror 1367-2, similar to mirror 967, and lenses 1343-2,similar to lenses 943, however located along a different path ofexcitation light 1383 than mirror 1367-1 and lenses 1343-1. Mirror1367-2 and lenses 1343-2 otherwise have similar respective functionalityas mirror 1367-2 and lenses 1343-2. Hence, light 1393-1, 1393-2 isproduced by light emitting material 1303 at locations respectivelyadjacent to lenses 1343-1, 1343-2. Lenses 1343-1 collect light 1393-1,and lenses 1343-2 collect light 1393-2 from light emitting material1303. Further, each of mirrors 1367-1, 1367-2 respectively conveys light1393-1, 1393-2 to dichroic structure 1365, which combines light 1393-1,1393-2 and reflects combined light 1393 to integrator 1351 and/orcollection optics. Dichroic structure 1365 hence comprises a combinationof dichroic mirrors which splits excitation light 1383 into portions,and reflects ach portion in different directions, and receives andcombines the resulting light 1393-1, 1393-2 emitted from light emittingmaterial 1303.

Furthermore mirrors 1367-1, 1367-2 can be located at the same radius ordifferent respective radii so that different regions of light emittingmaterial 1303 are excited by excitation light 1383. When mirrors 1367-1,1367-2 are located at the same radius, but 180° from each other, optics1307 can have circular symmetry and a counter-balance can be eliminatedfrom system 1300, as compared to previously described systems. However,when mirrors 1367-1, 1367-2 are located at different respective radii,and/or at angles different from 180°, and/or when optics 1307 do nothave circular symmetry, system 1300 can further include acounter-balance as in previously described systems.

It is yet further appreciated that implementations described in FIGS.1-13 can be combined as desired: for example, rotating optics can conveyexcitation light to different regions of a light emitting material in asame and/or different directions, to one or more light emittingmaterials at a same or different radii, using mirrors, dichroic mirrors,prisms and the like, with lasers and collection optics located on a sameor different sides.

In systems described heretofore, a surface of a heatsink and at leastone light emitting material comprises an annulus symmetrical about anaxis, and the optics are further configured to rotate along the surface.Specifically, heatsinks described heretofore comprise comprises toroidssymmetrical about the axis. In addition, rotating optics describedheretofore are configured to one or more of: receive excitation lightthrough the toroid; and convey the light collected from the at least onelight emitting material through the toroid. In some implementations, therotating optics are further configured to receive the excitation lightfrom a first side of the optics and convey the light collected from theat least one light emitting material back through the first side. In yetfurther implementations, the rotating optics are further configured toreceive the excitation light from a first side of the optics and conveythe light collected from the at least one light emitting materialthrough a second side opposite the first side.

However, other geometries are within the scope of presentimplementations. For example, a heatsink can comprise a cylinder, withat least one light emitting material located on an interior surface ofthe cylinder, and the optics (similar to rotating optics describedpreviously) can be configured to rotate within the cylinder.

For example, attention is next directed to FIG. 14 which depicts apartial cut away perspective view of a system 1400 comprising: acylindrical heatsink 1401; at least one light emitting material 1403-1,1403-2, 1403-3 located on an interior of cylindrical heatsink 1401, atleast a portion of at least one light emitting material 1403-1, 1403-2,1403-3 being circularly symmetrical around an axis 1405, for example alongitudinal axis of heatsink 1401, heatsink 1401 and the at least onelight emitting material 1403-1, 1403-2, 1403-3 being rotationally fixed;and optics 1407 configured to rotate relative to at least one lightemitting material 1403-1, 1403-2, 1403-3 around a rotational axis 1409that is coaxial with axis 1405 of at least one light emitting material1403-1, 1403-2, 1403-3. At least one light emitting material 1403-1,1403-2, 1403-3 will be interchangeably referred to hereaftercollectively as light emitting materials 1403 and generically as a lightemitting material 1403. While system 1400 comprises three light emittingmaterials 1403 disposed with circular symmetry on an interior ofheatsink 1401, other implementations can comprise fewer than three lightemitting materials 1403 or more than three light emitting materials1403. As depicted, the three light emitting materials 1403 emit red,green and blue light when excited by excitation light.

While not depicted in FIG. 14, system 1400 further comprises at leastone laser, similar to laser 117, and collection optics, which can besimilar to lens 150, integrator 151, etc. While also not depicted,system 1400 can further comprise a motor, a body and/or a framecomprising optics 1407, bearings, and a counterbalance, the motorconfigured to rotate optics about rotational axis 1409.

Optics 1407 comprises lenses 1443-1, 1443-2, 1443-3, each similar tolenses 143, and dichroic structures 1465-1, 1465-2, 1465-3. Lenses1443-1, 1443-2, 1443-3 will be interchangeably referred to hereaftercollectively as lenses 1443 and generically as lenses 1443. Similarly,dichroic structures 1465-1, 1465-2, 1465-3 will be interchangeablyreferred to hereafter collectively as dichroic structures 1465 andgenerically as a dichroic structure 1465. Optics 1407 comprises a set oflenses 1443 and a corresponding dichroic structure 1465 for each lightemitting material 1403. Each dichroic structure 1465 is similar todichroic structure 1365, and is located on, and aligned with, rotationalaxis 1409, however each dichroic structure 1465, other than dichroicstructure 1465-3, is at least partially transmissive of excitation light1483 so that excitation light is distributed to each dichroic structure1465 along rotational axis 1409. Each dichroic structure 1465 thenreflects excitation light 1483 to respective light emitting material1403, through respective lenses 1443, where excitation light 1483excites the respective light emitting material 1403 to emit light 1493.Light 1493 is collected by respective lenses 1443, and conveyed to therespective dichroic structure 1465, which reflects light 1493 alongrotational axis 1409 towards collection optics. Hence, each dichroicstructure 1465 is configured to transmit light 1493 received from aprevious dichroic structure.

Further, in implementations that do not include a blue light emittingmaterial, a last dichroic structure 1465 (e.g. dichroic structure1465-3) can be at least partially transparent to excitation light 1483so that blue excitation light can be mixed with green light, red light,and/or any colour produced by light emitting materials 1403 to producewhite light, as in system 600, including, but not limited to yellowlight, infrared light and the like.

As optics 1407 rotate about the interior of heatsink 1401, excitationlight 1483 excites light emitting materials 1403 in a circular mannerthereby distributing heat production on onto the interior surface ofheatsink 1401.

Furthermore, while heatsink 1401 is rotationally fixed, heatsink 1401can be linearly translated to increase the surface area of lightemitting materials 1403 which are excited, and hence the area of heatdistribution.

In other implementations where a heatsink comprises a cylinder, at leastone light emitting material can be located on an exterior surface of thecylinder, and rotating optics can be configured to rotate around theexterior surface of the cylinder; in other words, such systems aresimilar to system 1400, however the rotating optics rotate about theexterior; in such implementations, the rotating optics include mirrorsfor accepting excitation light along a rotation axis, conveying theexcitation light to a dichroic structure, and conveying light emitted bythe light emitting materials, as received from the dichroic structure.

For example, attention is next directed to FIG. 15 which depicts apartial cut away perspective view of a system 1500 comprising: acylindrical heatsink 1501; at least one light emitting material 1503located on an exterior of cylindrical heatsink 1501, at least a portionof at least one light emitting material 1503 being circularlysymmetrical around an axis 1505, for example a longitudinal axis ofheatsink 1501, heatsink 1501 and the at least one light emittingmaterial 1503 being rotationally fixed; and optics 1507 configured torotate relative to at least one light emitting material 1503 around arotational axis 1509 that is coaxial with axis 1505 of at least onelight emitting material. While system 1500 is depicted with one band oflight emitting material 1503 disposed with circular symmetry on anexterior of heatsink 1501, other implementations can comprise more thanone light emitting material 1503, as in system 1400. Furthermore, theband of light emitting material 1503 can comprise more than one lightemitting material arranged around the band.

While not depicted in FIG. 15, system 1500 further comprises at leastone laser, similar to laser 117, and collection optics, which can besimilar to lens 150, integrator 151, etc. While also not depicted,system 1500 can further comprise a motor, a body and/or a framecomprising optics 1507, bearings, and a counterbalance, the motorconfigured to rotate optics about rotational axis 1509.

Optics 1507 comprises lenses 1543, each similar to lenses 143, dichroicstructure 1565, and mirrors 1570, 1571, 1572, 1573. While only one setof lenses 1543 and one corresponding dichroic structure 1565 isdepicted, in implementations where system 1500 comprises more than oneband of light emitting material, system 1500 can comprise a set oflenses and a dichroic structure for each band of light emittingmaterial. Dichroic structure 1565 is similar to dichroic structure 1365,and is located on, and aligned with, rotational axis 1509; in someimplementations dichroic structure 1565 can be at least partiallytransmissive of excitation light 1583 so that at least a portion ofexcitation light 1583 is conveyed out of optics 1507. Where more thanone dichroic structure and more than one band of light emitting materialis present, the properties of the dichroic structures can be similar todichroic structures 1465.

In any event, excitation light 1583 is received at mirror 1570, which islocated on, and is centred rotational axis 1509; mirror 1570 isconfigured to reflect excitation light 1583 towards mirror 1571, whichin turn reflects excitation light to dichroic structure 1565. Dichroicstructure 1565 directs at least a portion of excitation light 1583 tolight emitting material 1503, through lenses 1543, and light 1593emitted by light emitting material 1503 is collected by lenses 1543which conveys light 1593 to dichroic structure 1565. Dichroic structure1565 directs light 1593 to mirror 1572, which reflects light 1593 (andalternatively a portion of excitation light 1583 transmitted by dichroicstructure 1565) to mirror 1573 located on, and centred on, rotationalaxis 1509. Mirror 1573 directs light 1593 out of optics 1507 towardscollection optics.

In alternative implementations, mirrors 1570, 1573 can be at leastpartially transmissive to excitation light 1583, and a portion ofexcitation light 1583 is transmitted through mirrors 1570,1573, tocombine excitation light 1583 with light 1593.

As described above optics 1507 (including mirrors 1570, 1571, 1572,1573) rotate about rotational axis 1509 so that an input path (andalternatively an output path) of excitation light 1583 and an outputpath of light 1593 are fixed along rotational axis 1509, while lightemitting material 1503 is excited along it's circumference to distributeheat production on heatsink 1501.

Persons skilled in the art will appreciate that there are yet evenfurther more alternative implementations and modifications possible. Forexample, attention is next directed to FIG. 16 which depicts a system1600 that is substantially similar to system 1300, with like elementshaving like numbers, but starting with a “16” rather than a “13”. Hence,system 1600 comprises: a heatsink 1601; at least one light emittingmaterial 1603 located on heatsink 1601; and, optics 1607 configured torotate relative to at least one light emitting material 1603 around arotational axis 1609 that is coaxial with axis 1605 of at least onelight emitting material 1603. System 1600 further comprises a frame1611, bearings 1613, a motor 1615, one or more lasers 1617, one or morelenses 1650 and an integrator 1651.

Further, optics 1607 is generally configured to: convey excitation light1683 from laser 1617 to at least two different portions of lightemitting material 1603; collect light 1693-1, 1693-2 emitted from the atleast two different portions of light emitting material 1603 excited byexcitation light 1683; and convey light 1693-1, 1693-2 collected fromthe at least two different portions of light emitting material 1603 torotational axis 1609 for emission there along.

Optics 1607 comprises lenses 1643-1, 1643-2, and mirrors 1667-1, 1667-2,each respectively similar to lenses 1343-1, 1343-2, and mirrors 1367-1,1367-2. However, as compared to optics 1307, optics 1607 comprisesbeamsplitter 1640, mirrors 1641-1, 1641-2, and beamcombiner 1665 inplace of dichroic structure 1365. For example, beamsplitter 1640comprises a mirror configured to split and/or reflect excitation light1683 from laser 1617 towards both of mirrors 1641-1, 1641-2;beamsplitter 1640 can hence comprise a corner mirror formed by twomirrors at about 90° to each other, centred on rotation axis 1609between laser 1617 and a plane formed by entrances to lenses 1643-1,1643-2.

In any event, beamsplitter 1640 is configured to convey excitation light1683 from laser 1617 to mirrors 1693-1, 1693-2, each of which in turnconvey excitation light 1683 to light emitting material 1603. Lightemitting material 1603 emits light 1693-1, 1693-2 which respectively istransmitted through mirrors 1641-1, 1641-2 to lenses 1643-1, 1643-2,which conveys light 1693-1, 1693-2 to beamcombiner 1665. Hence, each ofmirrors 1641-1, 1641-2 comprise a dichroic mirror configured to reflectexcitation light 1683 and transmit light 1693 emitted by light emittingmaterial 1603.

Beamcombiner 1665 is substantially similar to beamsplitter 1640, howeverbeamcombiner 1665 is configured to receive light 1693-1, 1693-2 fromeach of mirrors 1667-1, 1667-2 and combine light 1693-1, 1693-2 intolight 1693, as well as convey light 1693 to lens 1650 and integrator1651.

Hence, as depicted, optics 1607 convey excitation light 1683 to twospots on light emitting material 1603 (i.e. two rotation paths as optics1607 rotate) thus spreading heat production over a larger area of lightemitting material 1603. The two spots and/or rotation paths can be atsimilar or different radii.

In some implementations, frame 1611 can comprise beamsplitter 1640,mirrors 1641-1, 1641-2, and beamcombiner 1665; regardless, beamsplitter1640 and mirrors 1641-1, 1641-2 are configured to rotate along withremaining optics 1607.

Furthermore, in some implementations, beamsplitter 1640 and beamcombiner1665 can each comprise more than two respective mirrors; for exampleeach of beamsplitter 1640 and beamcombiner 1665 can comprise threemirrors (for example a corner of a mirrored cube and the like), andoptics 1607 comprises three sets of optics similar to the combination oflenses 1643-1, and mirrors 1641-1, 1667-1. Hence, in theseimplementations, heat production is spread over three spots and/orrotation paths at light emitting material 1603, which can be at similarand/or different radii. Further, when each path is at different radii,each path on light emitting material 1603 can comprise similar and/ordifferent light emitting materials.

Heretofore, implementations where a light emitting material is locatedon one side of a heatsink have been described; however techniques,apparatus and systems described herein can be adapted to heatsinks wherelight emitting material is located on both sides. For example, attentionis next directed to FIG. 17 which depicts a system 1700 that issubstantially similar to system 1600, with like elements having likenumbers, but starting with a “17” rather than a “16”. Hence, system 1700comprises: a heatsink 1701; at least two light emitting materials1703-1, 1703-2 (collectively referred to hereafter as light emittingmaterial 1703, and generically as a light emitting material 1703)located on opposing sides of heatsink 1701, each configured to emitlight of different wavelengths when excited; and, optics 1707 configuredto rotate relative to at least one light emitting material 1703 around arotational axis 1709 that is coaxial with axis 1705 of at least onelight emitting material 1703. System 1700 further comprises a frame1711, bearings 1713, a motor 1715, one or more lasers 1717, one or morelenses 1750 and an integrator 1751. Frame 1711 is depicted in twoportions, one on either side of heatsink 1701, which are assumed to berotationally connected, so that when one portion of frame 1711 isrotated by motor 1715 on bearings 1313, the other portion of frame 1711also rotates; such rotational connection can occur via a mechanicalconnection and the like, for example through an aperture of heatsink1701 and/or around. Alternatively, system 1700 can comprise a motor forrotating each portion of frame 1711.

Further, optics 1707 is generally configured to: convey excitation light1783 from laser 1717 to at least four different portions of lightemitting material 1703, two portions on each side of heatsink 1701;collect light 1793-1, 1793-2, 1793-3, 1794-4 emitted from the at leastfour different portions of light emitting material 1703 excited byexcitation light 1783; and convey light 1793-1, 1793-2, 1793-3, 1793-4collected from the at least four different portions of light emittingmaterial 1703 to rotational axis 1709 for emission there along.

Optics 1707 comprises beamsplitters 1740-1, 1740-2 (collectivelyreferred to hereafter as beamsplitters 1740, and generically as abeamsplitter 1740), mirrors 1741-1, 1741-2, 1741-3, 1741-4 (collectivelyreferred to hereafter as mirrors 1741, and generically as a mirror1741), lenses 1743-1, 1743-2, 1743-3, 1743-4, (collectively referred tohereafter as lenses 1743, and generically as lenses 1743), beamcombiners1765-1, 1765-2 (collectively referred to hereafter as beamcombiners1765, and generically as a beamcombiner 1765), and mirrors 1767-1,1767-2, 1767-3, 1767-4 (collectively referred to hereafter as mirrors1767, and generically as a mirror 1767).

Mirrors 1741-1, 1741-2 each comprise dichroic mirrors configured toreflect excitation light 1783 from laser 1717, and transmit light1793-1, 1793-2 emitted from light emitting material 1703-1, whilemirrors 1741-3, 1741-4 each comprise mirrors configured to reflectexcitation light 1783. Similarly, mirrors 1767-1, 1767-2 each comprisemirrors configured to reflect light 1793-1, 1793-2 emitted from lightemitting material 1703-1, while mirrors 1767-3, 1767-4 each comprisedichroic mirrors configured to transmit excitation light 1783 andreflect light 1793-3, 1793-4 emitted from light emitting material1703-1.

Otherwise beamsplitters 1740, mirrors 1741, lenses 1743, beamcombiners1765, and mirrors 1767 are each respectively similar to beamsplitter1640, mirrors 1641-1, 1641-2, lenses 1643-1, 1643-2, beamcombiner 1665,and mirrors 1667-1, 1667-2. However, beamsplitter 1740-1, mirrors1741-1, 1741-2, lenses 1743-1, 1743-2, beamcombiner 1765-1, and mirrors1767-1, 1767-2 are located on a same side of heatsink 1701 as lens 1750and integrator 1751; and beamsplitter 1740-2, mirrors 1741-3, 1741-4,lenses 1743-3, 1743-4, beamcombiner 1765-2, and mirrors 1767-3, 1767-4are located on an opposite side of heatsink 1701 as lens 1750 andintegrator 1751 and/or on a same side of heatsink 1701 as laser 1717.

Furthermore, beamsplitter 1740-2 is configured to both reflect (e.g.split) excitation light 1783 received at beamsplitter from laser 1717towards mirrors 1741-3, 1741-4, and transmit a portion of excitationlight 1783 towards beamcombiner 1765-2; and, beamcombiner 1765-2 isconfigured to combine light 1793-3, 1793-4 and transmit excitation light1783 received through beamsplitter 1740-2. Mirrors 1741-3, 1741-4 areeach positioned and/or configured to reflect excitation light 1783through respective mirrors 1767-3, 1767-4 and respective lenses 1743-3,1743-4, while lenses 1743-3, 1743-4 are respectively positioned and/orconfigured to collect light 1793-3, 1793-4 and convey emitted from lightemitting material 1703-2 (when excited by excitation light 1783) tomirrors 1767-3, 1767-4, which are respectively positioned and/orconfigured to reflect light 1793-3, 1793-4 towards beamcombiner 1765-2.Beamcombiner 1765-2 combines light 1763-3, 1793-4 and reflects light1763-3, 1793-4 through the aperture of heatsink 1701 towardsbeamsplitter 1740-1 along rotational axis 1709.

Beamsplitter 1740-1 is configured to reflect (e.g. split) excitationlight 1783 received at beamsplitter from laser 1717 towards mirrors1741-3, 1741-4, and transmit light 1763-3, 1793-4 towards beamcombiner1765-1; and beamcombiner 1765-1 is configured to combine light 1793-1,1793-2, received from mirrors 1767-1, 1767-2 with light 1793-3, 1793-4(i.e. beamcombiner 1765-2 is transparent to light 1763-3, 1793-4).Mirrors 1743-1, 1743-2 are each respectively positioned and/orconfigured to receive excitation light 1783 from beamsplitter 1740-1,and respectively reflect excitation light 1783 through lenses 1743-1,1743-2 to light emitting material 1703-1 so that light 1793-1, 1793-2 isemitted. Lenses 1743-1, 1743-2 are each respectively positioned and/orconfigured to collect light 1793-1, 1793-2 emitted from light emittingmaterial 1703-1, and respectively convey light 1793-1, 1793-2 to mirrors1767-1, 1767-2 which are positioned and/or configured to convey light1793-1, 1793-2 to beamcombiner 1765-1, where light 1793-1, 1793-2 iscombined with light 1793-3, 1793-4 into light 1793 and conveyed to lens1750 and integrator 1751.

While system 1700 is depicted as exciting light emitting material 1703at four different portions, each at about the same radius, in otherimplementations, one or more of the portions of light emitting materialcan be at a different radius.

Furthermore, while a specific combination of optical elements isdepicted in FIG. 17 for exciting and collecting light, othercombinations of optical elements are within the scope of presentimplementations, for example based on any of systems 100, 600, 800, 900,1000, 1100, and 1300 and/or portions thereof.

In any event, any of the systems described herein can be adapted toexcite light emitting material located on two sides of a heatsink usinga combination of mirrors, dichroic mirrors, prisms, and other opticalelements. For example, systems 1400 and 1500 can be combined to excitelight emitting material located on both an exterior and an exterior of acylindrical heatsink using one or more dichroic mirrors to convey lightto optics disposed about an exterior and interior of the cylindricalheatsink, and further one or more dichroic lenses to combine lightemitted from the exterior and interior light emitting materials.

While implementations described heretofore are all described withreference to systems where a light emitting material is located on aheatsink that can be reflective, rotating optics described herein can beadapted for use with systems where light emitting material and/or aheatsink are transmissive so that light emitted by the light emittingmaterial can be collected on both sides of the heatsink by opticsrotating there around.

Hence, described herein are various implementations of a system where aninput path (and alternatively an output path) of excitation light and anoutput path of light are fixed along a rotational axis of optics thatrotate about a rotationally fixed light emitting material and heatsink,to distribute light production at the light emitting material over thesurface of the heatsink, so that a static heat sink can be used to coolthe light emitting material.

In some implementations, excitation light need not be received along arotational axis of the optics. For example, attention is next directedto FIG. 18 which depicts a side view and partially cross-sectional viewof a system 1800 that is substantially similar to system 100, with likeelements having like numbers, but starting with an “18” rather than a“1”. In particular, system 1800 comprises a heatsink 1801; a lightemitting material 1803 located on heatsink 1801, at least a portion oflight emitting material 1801 being circularly symmetrical around an axis1805, heatsink 1801 and light emitting material 1803 being rotationallyfixed; a stationary light source 1817 configured to generate excitationlight 1833, excitation light 1833 configured to excite light emittingmaterial 1803 to produce emitted light (see FIG. 19), an incoming path1855 of excitation light 1833 forming a first angle θ1 with axis 1805 oflight emitting material 18031, first angle θ1 being greater than 0° andless than 90°; and, optics 1807 configured to rotate relative to lightemitting material 1803 around axis 1805 of light emitting material 1803(i.e. a rotational axis of optics 1807 is coaxial with axis 1805),optics 1807 comprising: a first mirror 1841 located on axis 1805 andforming a second angle θ2 with axis 1805, first mirror 1841 furtherlocated on incoming path 1855 of excitation light 1833, second angle θ2being greater than 0° and less than 90°; and a second mirror 1842parallel to first mirror 1841, first mirror 1841 configured to reflectexcitation light 1833 towards second mirror 1842, and second mirror 1842configured to reflect excitation light 1833 towards light emittingmaterial 1803.

Hence, as mirrors 1841, 1842 are parallel, the angle of incidence ofexcitation light 1833 onto light emitting material 1803 (as excitationlight 1833 is reflected from second mirror 1842) is about the same asfirst angle θ1 (with respect to a normal of light emitting material1803, which is generally normal to axis 1805).

It is appreciated that, in FIG. 18, heatsink 1801 and light emittingmaterial 1803 are depicted in cross-section, and comprise a toroidand/or annulus, the cross-section being along a diameter of the toroidand/or annulus; furthermore, optics 1807 are depicted schematically. Asdepicted, a surface of heatsink 1801 and light emitting material 1803comprises an annulus symmetrical about axis 1805, and optics 1807 arefurther configured to rotate along the surface. Furthermore, asdepicted, system 1800 further comprises one or more of a body and aframe (the body and/or frame hereinafter referred to as frame 1811) thatcomprises optics 1807. As in system 100, frame 1811 rotates on one ormore bearings 1813 located along an outer edge of frame 1811;alternatively, bearings 1813 can be located at a hub (not depicted) offrame 1811. System 1800 further comprises a motor 1815 configured torotate frame 1811, and hence optics 1807, relative to light emittingmaterial 1803; in addition, as depicted, frame 1811 further comprises anoptional counterbalance 1816 located so that a centre-of-mass of frame1811 is located along a rotational axis of optics, which is coaxial withaxis 1805. As depicted, system 1800 further comprises collection optics,located along rotational axis (and/or axis 1805), which can include, butis not limited to an integrator 1851. As in system 100, heatsink 1801can further comprise a static waterblock. In addition, while stationarylight source 1817 is depicted as being located on incoming path 1855,system 1800 can comprise optical components configured to steerexcitation light 1833 from stationary light source 1817 to incoming path1855 so that stationary light source 1817 need not be located onincoming path 1855.

Attention is next directed to FIG. 19, which is substantially similar toFIG. 18, with like elements having like numbers, however in FIG. 19,emitted light 1933 is depicted independent of excitation light 1833. Inparticular, emitted light 1933, which is emitted from light emittingmaterial 1803 when excited by excitation light 1833. In particular,emitted light 1933 is collected by second mirror 1842, and reflectedtowards first mirror 1841, which in turn reflects emitted light 1933along axis 1805, where emitted light can be collected by collectionoptics such as integrator 1851. In other words, first mirror 1841 andsecond mirror 1842 are further configured to reflect emitted light 1933from light emitting material 1803 away from light emitting material1833; in particular, first mirror 1841 and second mirror 1842 can befurther configured, as depicted, to reflect emitted light 1933 fromlight emitting material 1803 away from light emitting material 1833along axis 1805.

While excitation light 1833 and emitted light 1933 are not depictedconcurrently, it is appreciated that emitted light 1933 is emitted whenlight emitting material 1803 is irradiated with excitation light 1833and hence the processes depicted in FIGS. 18 and 19 are occurringsimultaneously and/or near simultaneously.

The geometry of mirrors 1841, 1842 is selected such that, as optics 1807rotate around the rotational axis, light emitting material 1803continues to be irradiated with excitation light 1833, similar to system100. For example, attention is next directed to FIG. 20, which issubstantially similar to FIG. 18 with like elements having like numbers,however optics 1807 (and counterbalance 1816) have rotated by 180° in acircle around the rotational axis (and/or axis 1805). In this position,first mirror 1841 continues to reflect excitation light 1833 towardssecond mirror 1842, which again reflects excitation light 1833 towardslight emitting material 1803. While not depicted, mirrors 1841, 1842reflect emitted light back along axis 1805.

It is further appreciated that paths of light through optics 1807 asdepicted herein is not meant to be exact, but rather is depictedschematically.

In any event, a geometry of mirrors 1841, 1842 is selected so that, asmirrors 1841, 1842 rotate, excitation light 1833 is reflected towardsdifferent areas of light emitting material 1803; in other words, asmirrors 1841, 1842 rotate, excitation light 1833 sweeps out a circle onlight emitting material 1803 to spread heat distribution along heat sink1801, which is rotationally fixed and can hence can be cooled withoutthe use of rotational cooling connections to heatsink 1801. Furthermore,a power of excitation light 1833 can be increased relative to systems inwhich a position of excitation light is fixed as heat production anddissipation is distributed around heatsink 1801.

With reference to any of FIGS. 18 to 20, a centre of first mirror 1841is located on axis 1805. Geometry of mirrors 1841, 1842 is furtherdescribed with reference to FIG. 21, which is substantially similar toFIG. 18, with like elements having like numbers, (but without excitationlight 1833 depicted). Specifically, a reflected path 2133 of excitationlight from first mirror 1841 to second mirror 1842 to light emittingmaterial 1803 is about equal to a length of a line 2155 extending alongincoming path 1855 of excitation light 1833 from a first intersectionpoint 2181 between first mirror 1841 and incoming path 1855 and a secondintersection point 2182 between axis 1805 and line 2155. Such conditionshold for each rotational position of mirrors 1841, 1842. In other words,a distance between mirrors 1841, 1842, and a distance between secondmirror 1842 and light emitting material 1803 are selected, using givenangles θ1, θ2, so that such the geometry depicted in FIG. 21 occurs ateach rotational position of mirrors 1841, 1842.

However, in some implementations, a centre of mirror 1841 need not be onaxis 1805. Rather, a centre of mirror 1841 can be off of axis 1841 aslong as, at each rotational position of mirrors 1841, 1842, thereflected path 2133 of excitation light from first mirror 1841 to secondmirror 1842 to light emitting material 1803 is about equal to a lengthof a line 2155 extending along incoming path 1855 of excitation light1833 from a first intersection point 2181 between first mirror 1841 andincoming path 1855 and a second intersection point 2182 between axis1805 and line 2155, at each rotational position of mirrors 1841, 1842.

It is further appreciated that as one or more of angles θ1, θ2 increasetowards 90° and/or decrease towards 0°, the distance from mirror 1842 tolight emitting material 1803 can increase significantly, and that atangles close to 0° and/or 90°, such distances can get very large.Indeed, 0° and/or 90° such distances can approach infinity, henceneither of given angles θ1, θ2 is equal to 0° or equal to 90°.

Practically, first angle θ1 can generally be greater than about 20° andless than about 75°. Similarly, second angle θ2 can generally be greaterthan about 20° and less than about 75°. In some non-limitingimplementations, as depicted, first angle θ1 is about 45° and secondangle is about 30°.

In some implementations, geometries of mirrors 1841, 1842 (e.g. anglesθ1, θ2) are selected so that excitation light 1833 impinges on lightemitting material 1803 at a normal angle, while in other implementationsgeometries of mirrors 1841, 1842 (e.g. angles 01, 02) are selected sothat excitation light 1833 impinges on light emitting material 1803 atan off-normal angle.

In some implementations, the angles of mirrors 1841, 1842 are fixed;however, in other implementations, angles of mirrors 1841, 1842 can beadjustable (i.e. first angle θ1 can be adjustable), as long as mirrors1841, 1842 remain parallel. In implementations where angles of mirrors1841, 1842 are adjustable, system 1800 can further comprise rotationaljoints, gears, pivots, and the like configured to adjust first angle θ1.For example, in these implementations, using a given second angle θ2 ofincoming path 1855 of excitation light, and a fixed distance betweenoptics 1807 and light emitting material 1803, first angle θ1 can beadjusted such that the conditions described with respect to FIG. 21 aremet. Hence, optics 1807 can be used with different systems where secondangle θ2 is changes from system to system. In some of theseimplementations, system 1800 can further comprise one or more of motors,stepper motors and the like configured to adjust first angle. However,in other implementations, such adjustments can be made manually.

In some of these implementations, a distance between optics 1807 andlight emitting material 1803 can also be adjustable; for example, one ormore of a position of heatsink 1801 and a position of optics 1807 (whichcan include a position of bearings 1813, motor 1815, etc.) can beadjustable so that the conditions described with respect to FIG. 21 canbe met. In such implementations, system 1800 can comprise rails and thelike configured to adjust a position of one or more of heatsink 1801 andoptics 1807. In some of these implementations, system 1800 can furthercomprise one or more of motors, stepper motors and the like configuredto adjust a position of one or more of heatsink 1801 and optics 1807.However, in other implementations, such adjustments can be mademanually.

Generally second mirror 1842 has a geometry and/or a length such thatmirror 1842 is not located on incoming path 1855 so as to not interferewith excitation light 1833. However, second mirror 1842 can be adaptedsuch that at least a portion can be located on incoming path 1855.

For example, attention is next directed to FIG. 22, which depicts asystem 2200 that is substantially similar to system 1800, with likeelements having like numbers. However in system 2200, second mirror 1842has been replaced with a second mirror 2242 that is substantiallysimilar to mirror 1842. However, second mirror 2242 comprises a portion2290 located on the incoming path 1855 of excitation light 1833 betweenstationary light source 1817 and first mirror 1841, portion 2290 ofsecond mirror 2242 configured to: transmit excitation light 1833 towardsfirst mirror 1841; and reflect emitted light 1933 (as in FIG. 19). Forexample portion 2290 can comprise a dichroic mirror and/or a polarizingbeam splitter (for example in implementations where excitation light1833 and emitted light 1933 have different polarization states). Indeed,in these implementations, all of second mirror 2242 can comprise thedichroic mirror, or only portion 2290 on the incoming path 1855. Suchimplementations enable a further degree of freedom in selecting ageometry of second mirror 2242 as second mirror 2242 can be located onincoming path 1855 in these implementations. Otherwise minors 1841, 1842can comprise reflecting mirrors and/or conventional reflecting mirrors,each configured to reflect both excitation light 1833 and emitted light1933.

System 1800 can be further adapted to include more than one lightemitting source. For example, attention is next directed to FIG. 23,which depicts a system 2300 that is substantially similar to system1800, with like elements having like numbers. However system 2300further comprises: at least a second stationary light source 2317 alsoconfigured to generate excitation light 1833, a respective geometry ofthe excitation light from second stationary light source 2317 similar toexcitation light 1833 of stationary light source 1817 other than aposition of an incident angle to first minor 1841 relative to mirror1841. It is appreciated that while excitation light 1833 from stationarylight source 1817 is not depicted in FIG. 23 for clarity, it isnonetheless present as in FIG. 18; similarly, emitted light 1933 is notdepicted for clarity. However, an incoming path 2355 of excitation light1833 from at least a second stationary light source 2317 also forms asame angle θ1 with axis 1805, however incoming path 2355, 1855 are notcongruent. Rather, as depicted, incoming path 2355 comprises a mirrorimage of incoming path 1855, with at least one second stationary lightsource 2317 and/or steering optics, located accordingly. In any event,incoming path 2355 and excitation light 1833 from second stationarylight source 2317 otherwise have a same geometry as incoming path 1855and excitation light 1833 from stationary light source 1817 as describedabove with respect to FIG. 21.

In addition, while incoming path 2355 is depicted as a mirror image ofincoming path 1855, in other implementations, incoming path 2355 can belocated radially anywhere around axis 1805 as long as the conditionsdescribed with respect to FIG. 21 are met. Hence, system 1800 can beadapted to include a plurality of stationary light sources arrangedradially around axis 1805 and/or arranged so that respective incomingpaths of respective excitation light are arranged radially around axis1805.

Hence, described herein are various implementations of systems where aninput of excitation light is fixed off of \a rotational axis of opticsthat rotate about a rotationally fixed light emitting material andheatsink, to distribute light production at the light emitting materialover the surface of the heatsink, so that a static heat sink can be usedto cool the light emitting material.

System described herein where rotating optics are configured to conveyexcitation light to a light emitting material on a heatsink at anoff-normal angle, can be adapted to include a thin disc laser as thelight emitting material.

For example, attention is next directed to FIG. 24 which depicts aschematic diagram of a cross-section of a thin disc laser structure 2400comprising a heatsink, a mirror 2402, a gain medium 2403 and anantireflective coating 2405. While not depicted, thin disc laserstructure 2400 can further comprise solder and/or metallic layersjoining the mirror/gain material/antireflective coating layers toheatsink 2401, for example between mirror 2402 and heatsink 2401.Indeed, the mirror/gain material/antireflective coating layers comprisethe actual thin disc laser. In general, when excitation light impingeson gain medium 2403, through antireflective coating 2405, gain medium2403 emits light according to laser processes. However, as a thicknessof gain medium 2403 is generally selected for such laser processes tooccur, and as the thickness is generally not large enough for the gainmedium 2403 to convert all incoming excitation light to emitted light ona first pass, a portion of the excitation light is reflected out of thindisc laser structure 2400 by mirror 2402.

Hence, some implementations of systems described herein, whereexcitation light impinges on a light emitting material at an off-normalangle, can be adapted to include a thin disc laser (e.g. as the lightemitting material) and a retroreflector configured to reflectedexcitation light reflected from the thin disc laser back towards thethin disc laser so that the recycled excitation light can be used tofurther excite the gain material.

For example attention is directed to FIG. 25 which depicts a system 2500similar to system 1800, with like elements having like numbers, howeverstarting with “25” rather than “18”. Specifically, system 2500comprises: A system comprising: a heatsink 2501; a gain medium 2503 of athin disc laser located on heatsink 2501, at least a portion of gainmedium 2503 being circularly symmetrical around an axis 2505, heatsink2501 and gain medium 2503 being rotationally fixed; 2507 opticsconfigured to rotate relative to gain medium 2503 around a rotationalaxis that is coaxial with axis 2505 of gain medium 2503, optics 2507configured to: receive excitation light 2533; convey excitation light2533 to gain medium 2503 at an off-normal angle as optics 2507 arerotating; collect light emitted from gain medium 2503 excited byexcitation light 2533; and, convey emitted light away from gain medium2503; and, at least one retroreflector 2543 configured to reflectexcitation light 2533 reflected from gain medium 2503 back towards gainmedium 2503.

As depicted optics 2507 comprise mirrors 2541, 2542 similar to mirrors1841, 1842 having similar geometric configurations with regards to firstangle θ1, second angle θ2 and an incoming path 2555 of excitation light2533, and axis 2505. However, angles θ1, θ2 are selected such thatexcitation light 2533 impinges on gain medium 2503 and a mirror of thethin disc laser on heatsink 2501 at an off-normal angle.

While not depicted, light emitted from gain medium 2503 will have asimilar to emitted light 1933 depicted in FIG. 19.

As with system 1800, system 2500 further comprises a frame 2511,bearings 2513, a motor 2515, an optional counterbalance 2516, at leastone stationary light source 2517, collection optics including, but notlimited to, an integrator 2551.

In other words, in system 2500, gain medium 2503 of the thin disc laseron heatsink 2501 replaces light emitting material 1803 relative tosystem 1800. Furthermore, retroreflector 2543 comprises a mirror locatedon path of excitation light 2533 reflected from a mirror of the thindisc laser on heatsink, which has a structure similar to that depictedin FIG. 24. Hence, excitation light 2533 that is not converted toemitted light by gain medium 2503 is reflected off the mirror of thethin disc laser according Snell's Law. As such, retroreflector 2543 islocated along a reflection path of excitation light 2533.

As depicted, a reflective surface of retroreflector 2543 facing gainmedium 2503 is about normal to reflected excitation light 2533 such thatexcitation light 2533 is reflected back towards gain medium 2503.Further, as depicted, optics 2507 comprises retroreflector 2543; hence,retroreflector 2543 rotates with optics 2507, such that retroreflector2543 reflects excitation light 2533 back to gain medium 2503 at allpositions of optics 2507 as optics 2507 rotates. Hence, as excitationlight 2533 sweeps out a circle on gain medium 2503, excitation light2533 reflected back to gain medium 2503 using retroreflector 2543 alsosweeps out a circle.

As a surface of heatsink 2501 and gain medium 2503 comprises an annulussymmetrical about axis 2505, and as optics 2507 are configured to rotatealong the surface of heatsink 2501, heat from the conversion process atgain medium 2503 is spread out along heatsink 2501, as optics 2507rotate. Hence power of excitation light 2533 can be increased relativeto a stationary thin disc laser and stationary excitation light system.Furthermore, as gain medium 2503 comprises an annulus, gain medium 2503effectively has a length that is a circumference of about a centre ofthe annulus, and as output of a gain medium of thin disc lasers can beproportional to the square of the length, gain medium 2503 can have anoutput that is much larger than a gain medium of a stationary thin disclaser where a path of excitation light is also stationary. For example,a circumference of gain medium 2503 is about five times that of a gainmedium of a reference thin disc laser, an output of gain medium 2503will be about twenty-five times that of the gain medium of the referencethin disc laser.

In other implementations, a reflective surface of retroreflector 2543facing gain medium 2503 can be off-normal to reflected excitation light2533 such that excitation light 2533 is reflected back towards gainmedium 2503 but to a different area of a surface of gain medium 2503such that excitation light 2533 is not reflected back into light source2517.

Other geometries of rotating optics are within the scope of presentimplementations. For example attention is next directed to FIG. 26 whichdepicts a system 2600 similar to system 2500 with like elements havinglike numbers however beginning with “26” rather than “25”. System 2600comprises: a heatsink 2601; a gain medium 2603 of a thin disc laserlocated on heatsink 2601, at least a portion of gain medium 2603 beingcircularly symmetrical around an axis 2605, heatsink 2601 and gainmedium 2603 being rotationally fixed; 2607 optics configured to rotaterelative to gain medium 2603 around a rotational axis that is coaxialwith axis 2605 of gain medium 2603, optics 2607 configured to: receiveexcitation light 2633; convey excitation light 2633 to gain medium 2603at an off-normal angle as optics 2607 are rotating; collect lightemitted from gain medium 2603 excited by excitation light 2633; and,convey emitted light away from gain medium 2603; and, at least oneretroreflector 2643 configured to reflect excitation light 2633reflected from gain medium 2603 back towards gain medium 2603. System2600 further comprises a frame 2611, bearings 2613, a motor 2615, anoptional counterbalance 2616, at least one stationary light source 2617,collection optics including, but not limited to, an integrator 2651.

As depicted optics 1807 comprise parallel mirrors 2641, 2642 similar tomirrors 1841, 1842 with mirror 2641 at an angle of about 45° to axis2605 such that emitted light 2634 from thin disc laser is collected bymirrors 2641, 2642 and conveyed along axis 2605 to collection optics,such as integrator 2651.

However, in contrast to system 2500, system 2600 comprises a stationarylight source 2617 located on an opposite side of optics 2607 (similar tosystem 900) and configured to emit excitation light 2633 along axis 2605and through an aperture of heatsink 2601 towards optics 2607. In theseimplementations, optics 2607 further comprise a mirror 2643 locatedalong axis 2605, mirror 2643 configured to reflect excitation light 2633received along axis 2605 to gain medium 2603 at an off-normal angle. Asmirror 2643 rotates around axis 2605 (i.e. as optics 2607 rotate),excitation light 2633 will sweep out a circle on gain medium 2603.

Retroreflector 2643, which in these implementations comprises aparabolic mirror, performs a similar function to retroreflector 2543,and is located on a reflection path of excitation light 2633. Hence,retroreflector 2643 reflects excitation light 2633 that is reflectedfrom mirror of the thin disc laser on heatsink 2601 back towards gainmedium 2603 for recycling.

Yet further geometries of rotating optics are within the scope ofpresent implementations. For example attention is next directed to FIG.27 which depicts a system 2700 similar to system 2500 with like elementshaving like numbers however beginning with “27” rather than “25”. System2700 comprises: a heatsink 2701; a gain medium 2703 of a thin disc laserlocated on heatsink 2701, at least a portion of gain medium 2703 beingcircularly symmetrical around an axis 2705, heatsink 2701 and gainmedium 2703 being rotationally fixed; 2707 optics configured to rotaterelative to gain medium 2703 around a rotational axis that is coaxialwith axis 2705 of gain medium 2703, optics 2707 configured to: receiveexcitation light 2733; convey excitation light 2733 to gain medium 2703at an off-normal angle as optics 2707 are rotating; collect lightemitted from gain medium 2703 excited by excitation light 2733; and,convey emitted light away from gain medium 2703; and, at least oneretroreflector 2743-1, 2743-2 configured to reflect excitation light2733 reflected from a mirror of the thin disc laser located on heatsink2701 back towards gain medium 2703. System 2700 further comprises aframe 2711, bearings 2713, a motor 2715, an optional counterbalance2716, at least one stationary light source 2717, collection opticsincluding, but not limited to, an integrator 2751.

As depicted optics 2707 comprise parallel mirrors 2741, 2742 similar tomirrors 2641, 2642 with mirror 2741 at an angle of about 45° to axis2705 such that emitted light (not depicted for clarity, but following asimilar path of emitted light 2634 as depicted in FIG. 26) from thindisc laser is collected by mirrors 2741, 2742 and conveyed along axis2705 to collection optics, such as integrator 2751.

In any event, as depicted, system 2700 comprises two stationaryretroreflectors 2743-1, 2743-2 which together comprise a retroreflectorsystem. Retroreflector 2743-1 comprises a parabolic reflector (depictedin cross-section, and hence having about circular symmetry with respectto axis 2705) that has a central aperture 2780 through which emittedlight is conveyed to collection optics, and an aperture 2781 on a pathof excitation light 2733 from stationary light source 2717, offset fromaperture 2780. Taken alone, the parabolic mirror is not strictly aretroreflector, but the parabolic mirror and retroreflector 2743-2(described below) together comprise a retroreflector system. Excitationlight 2733 passes through aperture 2781, reflects from mirror 2741 tomirror 2742, which then reflects excitation light 2733 at an off-normalangle to gain medium 2703. While the parabolic mirror is depicted asbeing symmetrical about axis 2705, in other implementations, parabolicmirror can comprise an asymetrical parabolic mirror that is notsymmetrical about axis 2705; indeed, any parabolic mirror that reflectslight to retroreflector 2743-2 and to optics 2707 as described herein,is within the scope of present implementations.

FIG. 27 depicts only incoming excitation light 2733, for clarity, andnot excitation light reflected from a mirror of the thin disc laser onheatsink 2701. Hence, attention is next directed to FIG. 28 whichdepicts system 2700 with reflected excitation light 2833 shown in theabsence of incoming excitation light 2733, for clarity, though it isappreciated that incoming excitation light 2733 is nonetheless present.In other words, reflected excitation light 2833 comprises incomingexcitation light 2733 that is not converted to emitted light by gainmedium 2703 but rather is reflected back through optics 2707 and then toretroreflector 2743-1, the parabolic mirror. Hence, the parabolic mirrorcomprises a diameter configured to capture all reflected excitationlight 2833 as optics 2707 rotates.

In any event, retroreflector 2743-1 reflects reflected excitation light2743-2 to a second stationary retroreflector 2743-2 which, as depicted,comprises a prism retroreflector configured both to direct reflectedexcitation light 2833 back towards retroreflector 2743-1 and offsetreflected excitation light 2833 around a radius of the parabolic mirror,such that reflected excitation light 2833 again reflects back towardsthe parabolic mirror of retroreflector 2743-1, which again reflectsreflected excitation light 2833 back through optics 2707 to gain medium2703; however, due to the offset, the path of reflected excitation light2833 is offset around a radius of the parabolic mirror, and hence is notreflected back into light source 2717. Hence, the path of retroreflectedexcitation light is not shown, but is assumed to be similar to a path ofreflected excitation light 2733, but in reverse and offset radially (andhence will be located above or below the page with respect to surface ofFIG. 28).

In some implementations, system 2700 can comprise further a plurality ofprism retroreflectors arranged radially around axis 2705 to retroreflectfurther reflected excitation light 2833 that again reflects from themirror of the thin disc laser on heatsink 2701 after being reflectedback to gain medium 2703 by retroreflectors 2743-1, 2743-2.

Such a combination of parabolic mirrors and prism retroreflectors, toretroreflect excitation light back to a thin disc laser in a radialarrangement can be referred to as multipass pumping, with a number ofpasses (e.g. a number of times that excitation light is recycled)corresponding to a number of prism retroreflectors.

Hence, described herein are various implementations of systems that useretroreflectors with rotating optics to excite a rotationally stationarythin disc laser on a, to distribute light production at the thin disclaser over the surface of the heatsink, so that a static heat sink canbe used to cool the light emitting material.

Persons skilled in the art will appreciate that there are yet morealternative implementations and modifications possible, and that theabove examples are only illustrations of one or more implementations.The scope, therefore, is only to be limited by the claims appendedhereto.

What is claimed is:
 1. A system comprising: a heatsink; a light emittingmaterial located on the heatsink, at least a portion of the lightemitting material being circularly symmetrical around an axis, theheatsink and the light emitting material being rotationally fixed; astationary light source configured to generate excitation light, theexcitation light configured to excite the light emitting material toproduce emitted light, an incoming path of the excitation light forminga first angle with the axis of the light emitting material, the firstangle being greater than 0° and less than 90°; and, optics configured torotate relative to the light emitting material around the axis of thelight emitting material, the optics comprising: a first mirror locatedon the axis and forming a second angle with the axis, the first mirrorfurther located on the incoming path of the excitation light, the secondangle being greater than 0° and less than 90°; and a second mirrorparallel to the first mirror, the first mirror configured to reflect theexcitation light towards the second mirror, and the second mirrorconfigured to reflect the excitation light towards the light emittingmaterial.
 2. The system of claim 1, wherein a reflected path of theexcitation light from the first mirror to the second mirror to the lightemitting material is about equal to a length of a line extending alongthe incoming path of the excitation light from a first intersectionpoint between the first mirror and the incoming path and a secondintersection point between the axis and the line.
 3. The system of claim1, wherein the first mirror and the second mirror are further configuredto reflect the emitted light from the light emitting material away fromthe light emitting material.
 4. The system of claim 1, wherein the firstmirror and the second mirror are further configured to reflect theemitted light from the light emitting material away from the lightemitting material along the axis.
 5. The system of claim 1, wherein thefirst angle is greater than about 20° and less than about 75°.
 6. Thesystem of claim 1, wherein the second angle is greater than about 20°and less than about 75°.
 7. The system of claim 1, further comprising:at least a second stationary light source configured to generate theexcitation light, a respective geometry of a respective incoming path ofthe excitation light from the at least a second stationary light sourcesimilar to a geometry of the incoming path of the excitation light fromthe stationary light source.
 8. The system of claim 1, wherein a portionof the second mirror is located on the path of the excitation lightbetween the stationary light source and the first mirror, the portion ofthe second mirror configured to: transmit the excitation light towardsthe first mirror; and reflect the excited light.
 9. The system of claim1, wherein the portion of the second mirror located on the path of theexcitation light between the stationary light source and the firstmirror comprises one or more of: a dichroic mirror; and, when theexcitation light and the emitted light have different polarizationstates, a polarizing beamsplitter.
 10. The system of claim 1, wherein acentre of the first mirror is located on the axis.
 11. The system ofclaim 1, further comprising one or more of a body and a frame, one ormore of the body and the frame comprising the optics.
 12. The system ofclaim 1, further comprising a motor configured to rotate the opticsrelative to the light emitting material.
 13. The system of claim 1,further comprising one or more of a body and a frame, one or more of thebody and the frame comprising the optics and a counter balance so that acenter of mass of one or more of the body and the frame is located alongthe rotational axis.
 14. The system of claim 1, wherein a surface of theheatsink and the light emitting material comprises an annulussymmetrical about the axis, and the optics are further configured torotate along the surface.
 15. The system of claim 1, wherein theheatsink further comprises a static waterblock.